The present invention relates to an apparatus for lifting a false floor, which sinks a false floor in a pool and vertically moves it to adjust the depth of water, keeping its horizontality.
It is desirable to adjust the depth of water in a swimming pool to stature of a swimmer. Accordingly, it is necessary to adjust the depth of water to the user's height age because the staure is different from the junior class to the senior class.
Recently, because of this, an apparatus for lifting a large false floor has been used, which sinks a false floor in a pool and vertically moves four corners of it by using a chain or a wirerope which is driven by a motor to adjust a depth of water, keeping its horizontality.
The lifting apparatus equipped the pantograph type jack below a false floor in order to lift the apparatus up as well as support the load of swimmers and, when the water is drained from the pool, the load of the false floor hanging in the air.
The method using a chain is disclosed in Japanese Patent Sho 63-58994, the method using a wirerope in Japanese Utility model Phyung 2-45239 and a pantograph type jack in Japanese Utility model Phyung 2-45240, respectively.
The method using a chain to lift a false floor controls the rotation of a sprocket which moves a chain above and below and easily vertically adjusts the false floor little by little. However, because the tension of a chain is not enough to bear a load of a false floor when the water in a pool is drained, the supporting equipment such as a jack must be installed under a false floor.
And, in the case where a wirerope is used for lifting a false floor, the tension of a wirerope is stronger than that of a chain so that it is possible to lift a false floor hanging at the air. However, though lifting units are equipped in four corners of a pool, it is difficult to precisely adjust a false above and below only by controlling rotation of each drum.
On the other hand, a pantograph jack for supporting a load of a false floor is most efficient when it is fully extended. But, when it is not fully extended, its supporting force is insufficient.
Furthermore, in the case where a pantograph jack is used for lifting a false floor, it needs an enough space for installing a pantograph jack between the floor surface of a pool and a false floor, so that a depth of water was shallowed as much.